The present invention relates to a fiber optic illumination system generally used during medical procedures.
During surgery, illumination is provided to clarify the doctor""s view. It is important for the illumination to have a sufficient light energy at the correct color temperature and color rendering index value. The illumination is typically provided by a lamp situated inside the illuminator with light directed to the surgical site by the use of a fiber bundle.
Halogen lamps have been used in the past for such illuminator systems. They are low cost, but the amount of light is usually less than desired and the color temperature is usually low. Higher end systems using xenon arc lamp provide a more desirable color temperature, which is almost the same as sunlight, and sufficient amount of light. The drawback is that these systems tend to be expensive due to the low intrinsic efficiency of the lamp and the required complex and expensive ballast. Metal halide and mercury lamps are also used for such purposes due to the higher efficiency of the lamps compared to xenon lamps, about 2 to 3 times more efficient, and as a result, provide a lower cost illuminator.
Due to the use of the metal halide and/or mercury inside discharge bulb, the output spectrum contains sharp spectral spikes, which correspond to the characteristics of the materials used. The effect of these spikes changes the characteristics of the output in terms of the color temperature, chromaticity and color rendering index. While filters have been used in metal halide lamp systems to correct the color temperature of the output, the chromaticity and color rendering index are largely neglected.
Accordingly, it is the goal of the present invention to provide an illumination system that includes a color correction system such that the output of the lamps with spikes in their spectra, such as metal halide lamps and mercury lamps, be corrected to provide light output with the desired color temperature, chromaticity, and color rendering index [xe2x80x9cCRIxe2x80x9d] at low cost.
To achieve this goal, the present invention provides a fiber optic illuminator for use at a surgical area to provide sufficient light energy having the desired characteristics of white light in terms of color temperature, chromaticity, and CRI such that the critical features at the surgical site can be clearly viewed. The illuminator comprises a high efficiency arc lamp usually with spikes in the output spectrum and condensing and collecting systems for focusing the light emitted from the arc lamp onto an output bundle of output fibers. In between the arc lamp and the output fiber optic is an optical filtering system such that the output of the arc lamp will be modified to produce an output at the fiber optic with the desired characteristics.